Power over Ethernet, PoE, is a technology used for providing power to devices over, typically, the same Ethernet cable that provides data connectivity. In recent developments PoE is used to power lighting devices, where each lighting device is a Powered Device, PD, according to the PoE standard (e.g. the IEEE 802.3af/at standards). Such a PD is powered by Power Sourcing Equipment, PSE, allowing for easy installation of a lighting system. It is desirable to make power distribution systems efficient such that power losses are small. A new PoE standard (i.e. the IEEE 802.3bt standard) is under development and increased power efficiency is one of the aspects this new standard will address.
Patent publication US 2013/154603 A1 discloses use of a current sense based Maintain Power Signature (MPS) such that a Powered Device (PD) can cause a Power Sourcing Equipment (PSE) to continue providing power to the PD.